Setup SSH agent for macOS High Sierra

This post is older than a year. Consider some information might not be accurate anymore.

Add to your ~/.ssh/config the option for every host.

Host *
   AddKeysToAgent yes
   UseKeychain yes

Check if ssh-agent is running.

ssh-agent

Add your key to the agent.

ssh-add

Check if key is added by listing all keys.

ssh-add -L